Impact Analysis

If the locality leak occurs, the TPM locality remains held and is not released properly. This can cause resource exhaustion or denial of service conditions within the TPM subsystem, potentially preventing other processes or operations from accessing the TPM correctly.

Such a leak could degrade system stability or security functions that rely on TPM, such as secure key storage or platform integrity measurements.

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Executive Summary

This vulnerability exists in the Linux kernel's TPM (Trusted Platform Module) driver for Infineon TPM devices using the I2C interface. Specifically, the function get_burstcount() can fail by returning -EBUSY on a timeout. When this failure occurs, the function returns immediately without releasing the locality that was acquired earlier in the tpm_tis_i2c_send() function. This improper handling leads to a locality leak, meaning the TPM locality remains held and is not properly cleaned up.

The fix involves using a goto statement to an error handling label (out_err) to ensure that the locality is properly released even when get_burstcount() fails.

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Mitigation Strategies

The vulnerability in the Linux kernel related to tpm_i2c_infineon involves a locality leak on get_burstcount() failure. To mitigate this vulnerability, you should update your Linux kernel to a version where this issue has been fixed.

Specifically, the fix ensures proper cleanup by using 'goto out_err' when get_burstcount() fails, preventing the locality leak.

Therefore, applying the latest kernel patches or upgrading to the fixed kernel version is the immediate step to mitigate this vulnerability.

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